Osteotomy procedure for correcting bone misalignment

ABSTRACT

An osteotomy procedure may be performed to correct a misalignment of a bone, such as a bunion deformity. In some examples, the osteotomy procedure involves making a spherical-shaped cut transecting a first metatarsal, thereby forming a first metatarsal portion having a spherical-shaped projection and a second metatarsal portion having a spherical-shaped recess. The method further involves moving the second metatarsal portion in at least two planes relative to the first metatarsal portion, thereby adjusting an anatomical alignment of the second metatarsal portion.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.15/687,994, filed Aug. 28, 2017, which claims the benefit of U.S.Provisional Patent Application No. 62/380,074, filed Aug. 26, 2016. Theentire contents of each of these applications are incorporated herein byreference.

TECHNICAL FIELD

This disclosure relates to devices and techniques for correcting bonesand, more particularly, to osteotomy techniques for correcting bonemisalignment.

BACKGROUND

Bones, such as the bones of a foot, may be anatomically misaligned. Incertain circumstances, surgical intervention is required to correctlyalign the bones to reduce patient discomfort and improve patient qualityof life.

SUMMARY

In general, this disclosure is directed to devices and techniques forcorrecting an anatomical misalignment of one or more bones. In someexamples, the technique involves making a generally crescent-shaped cuttransecting a bone to form a concave-shaped end and a convex-shaped end.The two resulting bone portions can be distracted, or separated fromeach other, and a second cut performed on the concave-shaped end of theresulting bone portion. The second cut may also be a generallycrescent-shaped cut but may be angled with respect to the concavityresulting from the first cut. For example, the first generallycrescent-shaped cut may form a saddle and the second generallycrescent-shaped cut may form an intersecting and offset saddle on a boneportion. The corresponding convex bone portion may be moved in multipleplanes to adjust the alignment of the bone portion. For example theconvex bone portion may be moved from the first saddle to the adjacentsecond saddle thereby facilitating realignment of the bone portion.

As one example, the technique may be performed on a first metatarsal tocorrect a bone alignment deformity, such as a bunion deformity. A firstgenerally crescent-shaped cut can be made parallel to or at an offsetangle relative to a frontal plane of the metatarsal transecting themetatarsal into two portions: one portion having a convex-shaped end andan opposed portion having a concave-shaped end. A second crescent shapecut may be made at an angle relative to a transverse plane bisecting theportion of the metatarsal having a convex-shaped end. This second cutmay chamfer or remove a portion of the convex-shaped bone end, such as adorsal lateral quadrant of the bone end. This can facilitate subsequentrealignment of the concave-shaped end of the opposing bone portionrelative to the convex-shaped end.

In another alternative, a bone realignment technique may be performed bymaking a single generally crescent-shaped cut instead of two generallycrescent-shaped cuts. In this technique, a generally crescent-shaped cutcan be made parallel to or at an offset angle relative to a frontalplane of the metatarsal transecting the metatarsal into a portion havinga convex-shaped end and an opposed portion having a concave-shaped end.A planar, transverse cut can then be made across the bone portion havingthe convex-shaped end resulting in three bone portions: a bone portionhaving a concave-shaped end, a bone portion having a planar end, and anintermediate bone portion having one planar end and one convex-shapedend. The intermediate bone portion can be translated along the arc ofthe curve formed by the concave-shaped end to reorient the metatarsal inthe transverse plane. The bone portion having the planar end can also berotated relative to the intermediate portion in the frontal plane. Aftersuitably reorienting the three bone portions relative to each other,three bone portions can be fixated together.

In other applications, a bone realignment technique may be performedwithout requiring multiple cuts. In these applications, a generallyspherical-shaped cutting member can be used to transect the bone beingrealigned. For example, a generally spherical-shaped cutting device canbe used to transect a first metatarsal resulting in a one bone portionhaving a generally spherical-shaped projection and an opposed boneportion having a generally spherical-shaped socket. The two boneportions can then be reoriented in multiple planes relative to eachother with or without performing additional cuts on a bone portion. Ineither case, after suitably realigning one bone portion relative toanother bone portion, the bone portions may be permanently fixated toeach other. For example, using plates, screws, pins and/or otherfixation hardware, one bone portion may be fixed to the opposed boneportion.

In yet further applications, a bone realignment technique may beperformed by transecting a bone with a substantially linear (e.g.,non-curved) cutting member by making a transverse cut across the bone.For example, a planar saw blade can be used to transect a firstmetatarsal resulting in a first bone portion and separate second bonepotion that each have planar cut end faces. The two bone portions canthen be reoriented in multiple planes relative to each other with orwithout performing additional cuts on a bone portion. After suitablyrealigning one bone portion relative to another bone portion, the boneportions may be permanently fixated to each other. For example, usingplates, screws, pins and/or other fixation hardware, one bone portionmay be fixed to the opposed bone portion.

Independent of the specific cutting technique or shape of cuttinginstrument used to cut the bone into two portions for realignment, adistal bone portion may be realigned relative to a proximal bone portionin multiple planes with or without the use of intra-operativefluoroscopy. In some examples, the clinician uses fluoroscopic imagingto visually assist in and/or guide realignment of the distal boneportion relative to the proximal bone portion. The relative positionand/or degree of angular rotation of the distal bone portion relative tothe proximal bone portion can be viewed by the clinician underfluoroscopic imaging and used to guide the degree of realignment. Theclinician may view the movement of the distal bone portion relative tothe proximal bone portion continuously while making the realignment orat one or more intervals to check the realignment made or being made.The clinician may use various anatomical landmarks visible viafluoroscopy, such as the rotational position of the distal metatarsalhead and/or the position of the sesamoid bones to help determine whenthe distal bone portion is suitably realigned.

In some examples, the clinician may introduce one or more pins into thedistal bone portion and/or proximal bone portion to help facilitaterealignment. For example, the clinician may insert a first pin in adistal bone portion and a second pin in a proximal bone portion. Theclinician can use the one or more pins as a grasping element, e.g., bygrasping an inserted pin and using the pin to manipulate and controlmovement of the distal bone portion relative to the proximal boneportion. The clinician may or may not monitor the relative positionand/or degree of angular rotation of the one or more pins duringmovement to help set the desired degree of realignment of the distalportion relative to the proximal portion. For example, the clinician maymonitor the relative position and/or degree of angular rotation betweena pin inserted into the proximal bone portion and another pin insertedin the distal bone portion during realignment to help set the desireddegree of realignment of the distal portion relative to the proximalportion. The clinician can monitor the position of the pin(s) visually(e.g., with the unaided eye) and/or using fluoroscopic imaging.

In one example, a method is described that involves making a firstcrescentic-shaped cut transecting a first metatarsal, thereby forming afirst metatarsal portion having a concave-shaped end and a secondmetatarsal portion having a convex-shaped end. The method furtherinvolves making a second crescentic-shaped cut across the concave-shapedend of the first metatarsal portion. In addition, the method includesmoving the second metatarsal portion in at least two planes relative tothe first metatarsal portion, thereby adjusting an anatomical alignmentof the second metatarsal portion.

In another example, a method is described that includes making aspherical-shaped cut transecting a first metatarsal, thereby forming afirst metatarsal portion having a spherical-shaped projection and asecond metatarsal portion having a generally spherical-shaped recess.The method also involves moving the second metatarsal portion in atleast two planes relative to the first metatarsal portion, therebyadjusting an anatomical alignment of the second metatarsal portion.

In another example, a method is described that includes making acrescentic-shaped cut transecting a first metatarsal, thereby forming afirst metatarsal portion having a concave-shaped end and a secondmetatarsal portion having a convex-shaped end. The method also involvesmaking a planar cut across the second metatarsal portion and offset fromthe concave-shaped end or the convex-shaped end, thereby forming aplanar end on the second metatarsal portion and an intermediate boneportion having the convex-shaped end. In addition, the method includesmoving the second metatarsal portion relative to the first metatarsalportion and the intermediate bone portion, thereby adjusting ananatomical alignment of the second metatarsal portion.

The details of one or more examples are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description and drawings, and fromthe claims.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are front views of a foot showing a normal firstmetatarsal position and an example frontal plane rotational misalignmentposition, respectively.

FIGS. 2A and 2B are top views of a foot showing a normal firstmetatarsal position and an example transverse plane misalignmentposition, respectively.

FIGS. 3A and 3B are side views of a foot showing a normal firstmetatarsal position and an example sagittal plane misalignment position,respectively.

FIGS. 4A-4D are flow diagrams illustrating example osteotomy techniquesfor correcting an anatomical alignment.

FIGS. 5A-5D show example procedural steps that can be performed tocorrect an anatomical misalignment of a bone.

FIGS. 6 and 7 are perspective and frontal views, respectively, showingoverlapping arcuate cuts that can be made to form first and secondcrescentic-shaped cuts, respectively.

FIGS. 8A and 8B show frontal views of an example proximal bone portionat different stages of an example osteotomy technique.

FIGS. 9A and 9B illustrate exemplary movement of a distal portion of afirst metatarsal relative to a proximal portion.

FIGS. 9C and 9D are frontal plane views showing examples sesamoid bonepositions before and after an example anatomical realignment,respectively.

FIG. 10 illustrates an example bone plate and example cutting guide thatmay be used to perform an osteotomy technique according to thedisclosure

FIGS. 11A-11C show example procedural steps that can be performed tocorrect an anatomical misalignment of a bone using a combination ofcrescentic-shaped and planar cuts.

FIG. 12 illustrates an example fixation arrangement that includes afirst bone plate and a second bone plate.

FIG. 13 is an illustration of an example generally spherical-shapedcutting blade that can be used to transect a metatarsal during a bonerealignment procedure.

FIGS. 14A and 14B are illustrations of example end faces formed bytransecting a first metatarsal with a generally spherical-shaped cuttingblade.

FIGS. 15A-15D illustrate example osteotomy procedure steps that may beperformed to realign a bone or bone portion using a planar cuttinginstrument according to the technique of FIG. 4D.

FIGS. 16A and 16B are example images showing how a guide pin can be usedduring to help facilitate realignment of one bone portion relative toanother bone portion.

FIGS. 17A and 17B are additional example images showing how guide pinscan be used during to help facilitate realignment of one bone portionrelative to another bone portion.

FIGS. 18A and 18B are fluoroscopic images showing example anatomicallandmarks that a clinician may monitor to guide realignment of a boneportion.

DETAILED DESCRIPTION

In general, the present disclosure is directed to devices and techniquesfor correcting a misalignment of one or more bones. The discloseddevices and techniques can be implemented in an osteotomy procedure inwhich a bone is surgically cut and/or a piece of bone is surgicallyremoved. In some examples, the technique is performed on one or morebones in the foot or hand, where bones are relatively small compared tobones in other parts of the human anatomy. For example, the foregoingdescription generally refers to example techniques performed on the footand, more particularly a metatarsal of the foot. However, the disclosedtechniques may be performed on other bones, such as the tibia, fibula,ulna, humerus, femur, or yet other bone, and the disclosure is notlimited in this respect unless otherwise specifically indicated. In someapplications, however, the disclosed techniques are used to correct amisalignment between a metatarsal (e.g., a first metatarsal) and asecond metatarsal and/or a cuneiform (e.g., a medial, or first,cuneiform), such as in a bunion correction surgery.

FIGS. 1-3 are different views of a foot 200 showing example anatomicalmisalignments that may occur and be corrected according to the presentdisclosure. Such misalignment may be caused by a hallux valgus (bunion),natural growth deformity, or other condition causing anatomicalmisalignment. FIGS. 1A and 1B are front views of foot 200 showing anormal first metatarsal position and an example frontal plane rotationalmisalignment position, respectively. FIGS. 2A and 2B are top views offoot 200 showing a normal first metatarsal position and an exampletransverse plane misalignment position, respectively. FIGS. 3A and 3Bare side views of foot 200 showing a normal first metatarsal positionand an example sagittal plane misalignment position, respectively. WhileFIGS. 1B, 2B, and 3B show each respective planar misalignment inisolation, in practice, a metatarsal may be misaligned in any two of thethree planes or even all three planes. Accordingly, it should beappreciated that the depiction of a single plane misalignment in each ofFIGS. 1B, 2B, and 3B is for purposes of illustration and a metatarsalmay be misaligned in multiple planes that is desirably corrected.

With reference to FIGS. 1A and 2A, foot 200 is composed of multiplebones including a first metatarsal 210, a second metatarsal 212, a thirdmetatarsal 214, a fourth metatarsal 216, and a fifth metatarsal 218. Themetatarsals are connected distally to phalanges 220 and, moreparticularly, each to a respective proximal phalanx. The firstmetatarsal 210 is connected proximally to a medial cuneiform 222, whilethe second metatarsal 212 is connected proximally to an intermediatecuneiform 224 and the third metatarsal is connected proximally tolateral cuneiform 226. The fourth and fifth metatarsals 216, 218 areconnected proximally to the cuboid bone 228. The joint 230 between ametatarsal and respective cuneiform (e.g., first metatarsal 210 andmedial cuneiform 222) is referred to as the tarsometatarsal (“TMT”)joint. The joint 232 between a metatarsal and respective proximalphalanx is referred to as a metatarsophalangeal joint. The angle 234between adjacent metatarsals (e.g., first metatarsal 210 and secondmetatarsal 212) is referred to as the intermetatarsal angle (“IMA”).

As noted, FIG. 1A is a frontal plane view of foot 200 showing a typicalposition for first metatarsal 210. The frontal plane, which is alsoknown as the coronal plane, is generally considered any vertical planethat divides the body into anterior and posterior sections. On foot 200,the frontal plane is a plane that extends vertically and isperpendicular to an axis extending proximally to distally along thelength of the foot. FIG. 1A shows first metatarsal 210 in a typicalrotational position in the frontal plane. FIG. 1B shows first metatarsal210 with a frontal plane rotational deformity characterized by arotational angle 236 relative to ground, as indicated by line 238.

FIG. 2A is a top view of foot 200 showing a typical position of firstmetatarsal 210 in the transverse plane. The transverse plane, which isalso known as the horizontal plane, axial plane, or transaxial plane, isconsidered any plane that divides the body into superior and inferiorparts. On foot 200, the transverse plane is a plane that extendshorizontally and is perpendicular to an axis extending dorsally toplantarly (top to bottom) across the foot. FIG. 2A shows firstmetatarsal 210 with a typical IMA 234 in the transverse plane. FIG. 2Bshows first metatarsal 210 with a transverse plane rotational deformitycharacterized by a greater IMA caused by the distal end of firstmetatarsal 210 being pivoted medially relative to the second metatarsal212.

FIG. 3A is a side view of foot 200 showing a typical position of firstmetatarsal 210 in the sagittal plane. The sagittal plane is a planeparallel to the sagittal suture which divides the body into right andleft halves. On foot 200, the sagittal plane is a plane that extendsvertically and is perpendicular to an axis extending proximally todistally along the length of the foot. FIG. 3A shows first metatarsal210 with a typical rotational position in the sagittal plane. FIG. 3Bshows first metatarsal 210 with a sagittal plane rotational deformitycharacterized by a rotational angle 240 relative to ground, as indicatedby line 238.

A bone positioning technique according to the disclosure can be usefulto correct an anatomical misalignment of a bones or bones. In someapplications, the technique involves realigning a metatarsal or aportion thereof, relative to an adjacent cuneiform and/or adjacentmetatarsal. The metatarsal undergoing realignment may be anatomicallymisaligned in the frontal plane, transverse plane, and/or sagittalplane, as illustrated and discussed with respect to FIGS. 1-3 above.Accordingly, realignment may involve releasing the misaligned metatarsalor portion thereof for realignment and thereafter realigning themetatarsal or portion in one or more planes, two or more planes, or allthree planes. After suitably realigning the metatarsal or portionthereof, the metatarsal or portion thereof can be fixated to hold andmaintain the realigned positioned.

While a metatarsal can have a variety of anatomically aligned andmisaligned positions, in some examples, the term “anatomically alignedposition” means that an angle of a long axis of first metatarsal 210relative to the long axis of second metatarsal 212 is about 10 degreesor less in the transverse plane and/or sagittal plane. In certainembodiments, anatomical misalignment can be corrected in both thetransverse plane and the frontal plane. In the transverse plane, anormal IMA 234 between first metatarsal 210 and second metatarsal 212 isless than about 9 degrees. An IMA 234 of between about 9 degrees andabout 13 degrees is considered a mild misalignment of the firstmetatarsal and the second metatarsal. An IMA 234 of greater than about16 degrees is considered a severe misalignment of the first metatarsaland the second metatarsal. In some embodiments, methods according to thedisclosure are utilized to anatomically align first metatarsal 210 or aportion thereof by reducing the IMA from over 10 degrees to about 10degrees or less (e.g., to an IMA of about 1-5 degrees), including tonegative angles of about −5 degrees or until interference with thesecond metatarsal, by positioning the first metatarsal at a differentangle with respect to the second metatarsal.

With respect to the frontal plane, a normal first metatarsal will bepositioned such that its crista prominence is generally perpendicular tothe ground and/or its sesamoid bones are generally parallel to theground and positioned under the metatarsal. This position can be definedas a metatarsal rotation of 0 degrees. In a misaligned first metatarsal,the metatarsal is axially rotated between about 4 degrees to about 30degrees or more. In some embodiments, methods according to thedisclosure are utilized to anatomically align the metatarsal by reducingthe metatarsal rotation from about 4 degrees or more to less than 4degrees (e.g., to about 0 to 2 degrees) by rotating the metatarsal withrespect to the medial cuneiform.

FIG. 4A is a flow diagram illustrating an example osteotomy techniquefor correcting an anatomical alignment. The technique will be describedwith respect to first metatarsal 210 although can be performed on otherbones, as discussed above. With reference to FIG. 4A, the exampletechnique involves making a first crescentic-shaped cut transectingmetatarsal 210 (300). The first cut separates the first metatarsal 210into two portions: a proximal portion and a distal portion. One of theportions can have a concave-shaped end with a radius corresponding tothe radius of the crescentic-shaped cut while the other portion can havea corresponding concave-shaped end of the same radius. The two portionscan be distracted, or separated by force, to provide opposed endsseparated from each other.

The technique of FIG. 4A further involves making a secondcrescentic-shaped cut across the concave-shaped end of theconcave-shaped bone portion (302). The second crescentic-shaped cut canbe made at an offset angle relative to the first crescentic-shaped cut,providing intersecting cut arcs that define multiple intersectingconcave regions on the end face of the bone. For example, secondcrescentic-shaped cut may be used to chamfer a dorsal-lateral quadrantof the concave-shaped bone portion, providing a second concave pocketoffset from a centered concavity formed upon making the firstcrescentic-shaped cut. This second concave pocket may provide a regionin which the convex-shaped end of the opposite bone portion can berotated into to rotationally realign one bone portion relative to theother bone portion.

For example, the illustrated technique includes moving one bone portionrelative to another bone portion to adjust an alignment of the boneportions relative to each other (304). In some examples, the distalportion of the transected first metatarsal 210 is rotated relative tothe proximal portion of the transected metatarsal. The distal portion ofthe transected first metatarsal 210 may be rotated in the frontal planeand/or pivoted in the transverse plane and/or pivoted in the sagittalplane to help correct an anatomical misalignment of the distal portionof the metatarsal. In some examples, the distal portion of the firstmetatarsal 210 is rotated about an axis extending through the frontalplane so the medial side is moved dorsally and/or the distal portion ofthe first metatarsal 210 is moved laterally in the transverse planeand/or plantarly in the sagittal plane. For example, the distal portionof the transected first metatarsal 210 may be moved from an anatomicallymisaligned position relative to second metatarsal 212 and/or the medialcuneiform 222 to an anatomically aligned position. During movement, theend face of the distal portion of the first metatarsal 210 created bymaking the first crescentic-shaped cut can shift relative to the endface of the proximal portion of the first metatarsal created by makingthe cut.

In some example, the end face of the distal portion of the firstmetatarsal 210 created by making the first crescentic-shaped movesmedially relative to the end face of the proximal portion of the firstmetatarsal created by making the cut. This base shift can cause thelateral side of the distal portion to move from being aligned with thelateral side of the proximal portion to being medially offset relativeto the lateral face. For example, the lateral side of the distal portionof first metatarsal 210 may move into a concave pocket formed in themedial-lateral quadrant of the end face of the proximal portion of thefirst metatarsal by making the second crescentic-shaped cut. In theseapplications, the second pocket formed by making the secondcrescentic-shaped cut may reduce or eliminate bone-on-bone interferencethat may otherwise occur between the proximal and distal portions of thefirst metatarsal during realignment.

After suitably moving the two transected bone portions relative to eachother, the bone portions can be fixated to each other to secure and holdthe new realigned position achieved through movement (306). The boneportions can be fixated using pins, plates, screws, or other fixationdevices to provide stability during the healing process. In one example,a bone plate is secured on the dorsal-medial side of the distal andproximal bone portions across the joint formed by transecting the firstmetatarsal 210 into the two bone portions. Additionally oralternatively, a bone plate may be secured on a different portion of thebones, such as helical bone plate that extends from a medial side of thedistal bone portion to a plantar side of the proximal bone portionand/or from a plantar side of the distal bone portion to a medial sideof the proximal bone portion. Additional details on example bone platingconfigurations that can be used are described in U.S. patent applicationSer. No. 14/990,368, entitled “BONE PLATING SYSTEM AND METHOD” and filedon Jan. 7, 2016, the entire contents of which are incorporated herein byreference.

FIG. 4B is a flow diagram illustrating another example technique forcorrecting an anatomical alignment. The example technique involvesmaking a generally spherical-shaped cut transecting a metatarsal 210(450). The generally spherical-shaped cut separates the first metatarsal210 into two portions: a proximal portion and a distal portion. One ofthe portions can have a generally spherical-shaped end while the end ofthe opposed bone portion can have a corresponding generallyspherical-shaped socket.

To make the generally spherical-shaped cut, a generally spherical-shapedcutting instrument can be translated through an arc that transects thefirst metatarsal. The cutting instrument can be translated in anydirection across the metatarsal, including from the dorsal to theplantar side of the metatarsal or vice versa, or the medial to thelateral side of the metatarsal or vice versa. The cutting instrument canbe translated across the metatarsal such that the resulting proximalportion defines the generally spherical-shaped ball and the distalportion defines the corresponding generally spherical-shaped socket.Alternatively, the cutting instrument can be translated across themetatarsal such that the resulting distal portion defines the generallyspherical-shaped ball and the proximal portion defines the correspondinggenerally spherical-shaped socket.

The generally spherical-shaped ends formed by making the transecting cutaccording to the technique of FIG. 4B may have a substantially constantradius (or, in some embodiments, constant radius) of curvature from ageometric center of the shape or may have a radius of curvature thatvaries across the face from the geometric center of the shape. Forexample, the generally spherical-shaped ends may have a parabolic orother spheroidal shape that provides one rounded end that fits into acup-like depression of an opposed end. The generally spherical-shapedends can be achieved using a cutting instrument with a generallyspherical-shaped blade or cutting instruments having alternative shapesthat are moved through the bone during transection to achieve thegeneral spherical-shape. In some examples, a generally spherical-shapedcutting instrument is used that has a generally spherical-shaped cuttingblade having a diameter ranging from 6 millimeters to 30 millimeters,although cutting blades of other dimensions can also be used. The radiusof curvature of the generally spherical-shaped cutting blade may beconstant across the blade or may vary by less than a threshold amount,such as plus or minus 30%, plus or minus 20%, plus or minus 10%, plus orminus 5%, or plus or minus 1%.

After cutting the first metatarsal into two portions using a generallyspherical-shaped cutting instrument, the technique of FIG. 4B includesmoving one bone portion relative to another bone portion to adjust analignment of the bone portions relative to each other (452). In someexamples, the distal portion of the transected first metatarsal 210 isrotated relative to the proximal portion of the transected metatarsal.The distal portion of the transected first metatarsal 210 may be rotatedin the frontal plane and/or pivoted in the transverse plane and/orpivoted in the sagittal plane to help correct an anatomical misalignmentof the distal portion of the metatarsal, as described herein.

After suitably moving the two transected bone portions relative to eachother, the bone portions can be fixated to each other to secure and holdthe new realigned position achieved through movement (452). The boneportions may or may not be provisionally fixated before beingpermanently fixated together. In either case, the portions can bepermanently fixated using pins, plates, screws, staples or otherfixation devices to provide stability during the healing process, asdiscussed above with respect to FIG. 4A and also discussed below withrespect to FIGS. 9A-9C and 10.

FIG. 4C is a flow diagram illustrating another example osteotomytechnique for correcting an anatomical alignment. The example techniqueinvolves making a crescentic-shaped cut transecting metatarsal 210(456). The cut separates the first metatarsal 210 into a proximalportion and a distal portion. One of the portions can have aconcave-shaped end with a radius corresponding to the radius of thecrescentic-shaped cut while the other portion can have a correspondingconcave-shaped end of the same radius. In some examples, the proximalportion has the concave-shaped end and the distal portion has theconvex-shaped end. The two portions may or may not be distracted toprovide opposed ends separated from each other.

The technique of FIG. 4C further involves making a transverse, planarcut across the distal bone portion (458). The transverse, planar cutremoves the concave- or convex-shaped end of the distal bone portion,forming a third or intermediate bone portion having the concave- orconvex-shaped end previously defined by the distal bone portion. Theends of the distal bone portion and the intermediate bone portion facingeach other may be planar.

After making the transverse, planar cut across, the technique furtherincludes moving the distal metatarsal portion relative to the proximalmetatarsal portion and/or the intermediate metatarsal portion to adjustan alignment of the distal and proximal bone portions relative to eachother (460). In some examples, the distal portion of the transectedfirst metatarsal 210 may be rotated in the frontal plane and/or pivotedin the transverse plane and/or pivoted in the sagittal plane to helpcorrect an anatomical misalignment of the distal portion of themetatarsal. For example, the distal portion and the intermediate portionmay each be moved in the transverse plane relative to the proximalportion, e.g., either the same distance or different distances. In someexamples, the proximal ends of the distal portion and the intermediateportion are each translated medially in the transverse plane, e.g.,causing the distal ends to pivot laterally to close the IMA.

In addition to or in lieu of translating the distal portion and theintermediate portion in the transverse plane, the distal portion may berotated relative to the intermediate portion in the frontal plane.During movement, the planar proximal end face of the distal portion canrotate relative to the planar distal end face of the intermediateportion. In some examples, the distal portion is pivoted in the sagittalplane to also adjust the alignment of the distal portion in the sagittalplane.

After suitably moving the three transected bone portions relative toeach other, the bone portions can be fixated to each other to secure andhold the new realigned position achieved through movement (462). Thebone portions may or may not be provisionally fixated before beingpermanently fixated together. In either case, the portions can bepermanently fixated using pins, plates, screws, staples or otherfixation devices to provide stability during the healing process, asdiscussed above with respect to FIG. 4A and also discussed below withrespect to FIGS. 9A-9C and 10.

FIG. 4D is a flow diagram illustrating another example technique forcorrecting an anatomical alignment. The example technique involvesmaking a planar cut transecting a metatarsal 210 (600). The planar cutseparates the first metatarsal 210 into two portions: a proximal portionand a distal portion. Both bone portions may have planar cut end faces.

To make the planar cut, a planar cutting instrument such as a saw bladecan be translated through the first metatarsal. The cutting instrumentcan be translated in any direction across the bone, including from thedorsal to the plantar side of the metatarsal or vice versa, or themedial to the lateral side of the metatarsal or vice versa. The cuttinginstrument can be translated through the first metatarsal parallel tothe frontal plane or at a non-zero degree angle relative to the frontalplane. Likewise, the cutting instrument can be translated through thefirst metatarsal orthogonal to the transverse plane or at a non-zerodegree angle relative to the transverse plane. Independent of the angleat which the planar cutting instrument is passed through the bone, theend faces formed by making the transecting cut according to FIG. 4D maybe planar (e.g., non-curved).

After cutting the first metatarsal into two portions using a planarcutting instrument, the technique of FIG. 4D includes moving one boneportion relative to another bone portion in multiple planes to adjust analignment of the bone portions relative to each other (602). In someexamples, the distal portion of the transected first metatarsal 210 isrotated relative to the proximal portion of the transected metatarsal.The distal portion of the transected first metatarsal 210 may be rotatedin the frontal plane and/or translated in the transverse plane and/ortranslated in the sagittal plane to help correct an anatomicalmisalignment of the distal portion of the metatarsal, as describedherein.

After suitably moving the two transected bone portions relative to eachother, the bone portions can be fixated to each other to secure and holdthe new realigned position achieved through movement (604). The boneportions may or may not be provisionally fixated before beingpermanently fixated together. In either case, the portions can bepermanently fixated using pins, plates, screws, staples or otherfixation devices to provide stability during the healing process, asdiscussed above with respect to FIG. 4A and also discussed below withrespect to FIGS. 9A-9C and 10.

FIGS. 5A-5D show example procedural steps that can be performed tocorrect an anatomical misalignment of a bone. As shown in FIG. 5A, thefirst metatarsal 210 is positioned in the transverse plane and defines amedial side 310, lateral side 312, dorsal side 314, and plantar side316. To transect the first metatarsal 210, a first crescentic-shaped cut318 can be made to form a proximal bone portion 320 and a distal boneportion 322. In different examples, the crescentic-shaped cut can makeusing a cutting instrument that makes a planar cut (e.g., planar blade,rotary cutter) that is translated through a curved arc or acurved-shaped cutting blade that is translated linearly to form thegenerally crescent-shaped cut. For example, the crescentic-shapedcutting blade may be translated parallel to the frontal plane of firstmetatarsal 210 (e.g., either from the dorsal to plantar side or plantarto dorsal side) to form the first crescentic-shaped cut 318.

In general, the terms crescent and crescentic are used interchangeablyin this disclosure and refer to an arcuate shape having a uniform radiusof curvature. The crescentic-shaped cut 318 defines new end facesseparating the proximal portion 320 from the distal portion 322. In theillustration of FIG. 5B, the end face 324 of proximal portion 320 has aconcave shape while the end face 326 of distal portion 322 has acorresponding convex shape. In other applications, the arc can beflipped so the end face 324 of proximal portion 320 has the convex shapewhile the end face 326 of distal portion 322 has the correspondingconcave shape.

While the crescentic-shaped cut 318 can be made at any location alongthe length of first metatarsal 210, in some examples, the cut is made onthe proximal portion of the metatarsal. For example, thecrescentic-shaped cut 318 may be made on the proximal-most half of thefirst metatarsal 210, such as the proximal-most quarter, orproximal-most eighth of the first metatarsal. Positioning thecrescentic-shaped cut 318 closer to the TMT joint may be useful toposition the center of rotation, or Center of Rotational Angulation(“CORA”), formed between the proximal portion 320 and distal portion322, farther back proximally along the length of foot 200 to approach amore anatomically correct alignment.

With reference to FIG. 5C, the distal portion 322 of the firstmetatarsal 210 can be distracted, or separated, from the proximalportion 320 of the metatarsal to expose the end faces of the respectivebone portions. Thereafter, a second crescentic-shaped cut 328 can bemade across the concave-shaped end face to create a second concavity 332intersecting with a first concavity 330 formed by making the firstcrescentic-shaped cut 318. The second crescentic-shaped cut 328 mayremove a section of bone to allow the end face of the distal boneportion 322 to be shifted in the medial direction 310 to realign thebone portion in one or more planes relative to proximal portion 320.

In some examples, the second crescentic-shaped cut 328 is formed byrotating the cutting instrument in the frontal plane relative to theposition of the cutting instrument when making the firstcrescentic-shaped cut 318. Thereafter, the cutting instrument can betranslated across the bone, e.g., causing the cutting instrument to formthe second crescentic-shaped cut 328 at an angle relative to the angleat which the first crescentic-shaped cut 318 was made. FIGS. 6 and 7 areperspective and frontal views, respectively, showing overlapping arcuatecuts that can be made to form the first and second crescentic-shapedcuts 318 and 328, respectively. The arcuate cuts are shown overlappingon a unitary first metatarsal 210 for purposes of illustration althoughin practice, one of the cuts (either the first crescentic-shaped cut 318or second crescentic-shaped cut 328) will be made to separate themetatarsal into two portions followed by the other of the two cuts.

In FIGS. 6 and 7, the first and second crescentic-shaped cuts 318 and328 are made relative to a sagittal plane 340, a transverse plane 342,and a frontal plane 344. The sagittal plane 340 extends in the proximalto distal direction along the length of first metatarsal 210 and bisectsmetatarsal in the dorsal 314 to plantar 316 directions. The transverseplane 342 extends in the proximal to distal direction along the lengthof first metatarsal 210 and bisects metatarsal in medial 310 to lateral312 directions. The frontal plane 344 transects the first metatarsal 210at one particular location along the length of the metatarsal in theproximal to distal direction.

In the illustrated example, the first crescentic-shaped cut 318 is madeparallel to the frontal plane 344, e.g., perpendicular to the transverseplane 342. However, the first crescentic-shaped cut 318 can be angled inthe sagittal plane 340 (either in the proximal-to-distal direction ordistal-to-proximal direction), such as an angle ranging from 2 degreesto 15 degrees relative to the frontal plane 344, such as from 5 degreesto 10 degrees relative to the frontal plane.

The second crescentic-shaped cut 328 may be made at an angle relative tothe transverse plane 342. For example, the second crescentic-shaped cut328 may be made at an acute angle 348 relative to the transverse plane.In some examples, the acute angle ranges from 10 degrees to 35 degrees,such as from 15 degrees to 25 degrees, or from 18 degrees to 23 degrees.The second crescentic-shaped cut 328 may be made in the same frontalplane as the frontal plane in which the first crescentic-shaped cut 318is made or may be offset. For example, the second crescentic-shaped cut328 may be at an angle ranging from 2 degrees to 15 degrees relative tothe frontal plane 344, such as from 5 degrees to 10 degrees relative tothe frontal plane.

FIGS. 8A and 8B show frontal views of the proximal bone portion 320 atdifferent stages of the example osteotomy technique. FIG. 8A illustratesthe end face of proximal bone portion 320 after the first cut but priorto the second cut, resulting in the first concavity 330. The curvatureof first crescentic-shaped cut 318 is illustrated in FIG. 8A overlayingthe end face to show how the curvature has been formed by the generallycrescent-shaped cut. FIG. 8B illustrates the end face of proximal boneportion 320 after the second cut, resulting in second concavity 332. Thecurvature of second crescentic-shaped cut 328 is illustrated in FIG. 8Boverlaying the end face to show how the curvature has intersected withthe curvature of the first cut. As shown in this example, a section ofbone in a dorsal lateral quadrant of the end face has been removed bythe second crescentic-shaped cut 328, thereby forming a second pocket orsaddle (second concavity 332) that intersects with the main pocket orsaddle (first concavity 330) formed by the first cut.

In practice, the same cutting instrument (e.g., having the same radiusof curvature) used to form the first crescentic-shaped cut 318 may beused to form the second crescentic-shaped cut 328. Alternatively, adifferent sized and/or shaped cutting instrument may be used to form thesecond crescentic-shaped cut 328 from that used to form the first cut.In some examples, the cutting instrument used to form the first and/orsecond crescentic-shaped cuts 318, 328 has a radius of curvature rangingfrom 3 millimeters to 15 millimeters.

After forming the first and second crescentic-shaped cuts 318, 328, theclinician may move one bone portion (e.g., distal portion 322) relativeto another bone portion (e.g., proximal portion 320) to realign thatbone portion relative to the medial cuneiform 222 and/or an adjacentmetatarsal, such as second metatarsal 212 (FIGS. 1A and 2A). Forexample, as discussed above with respect to FIG. 4A, the distal portion322 of the transected first metatarsal 210 may be moved from ananatomically misaligned position relative to second metatarsal 212and/or the medial cuneiform 222 to an anatomically aligned position.During movement, the end face of the distal portion 322 of the firstmetatarsal 210 created by making the first crescentic-shaped cut 318 canshift relative to the end face of the proximal portion 320 of the firstmetatarsal created by making the cut.

In some examples, the lateral side of the end face of the distal portion322 is repositioned in contact with a portion of end face of proximalportion 320 created by making the second crescentic-shaped cut 328.FIGS. 9A and 9B illustrate exemplary movement of a distal portion 322relative to a proximal portion 320, e.g., to reduce the IMA in thetransverse plane and/or reduce the extent of angular deformity in thefrontal and/or sagittal planes. FIG. 9A illustrates example movement ofdistal portion 322 relative to proximal portion 320 to correct acomparatively minor deformity while FIG. 9B illustrates example movementfor a more severe deformity.

To reposition the distal portion 322 relative to the proximal portion320 in the example of FIGS. 9A and 9B, the distal portion 322 can berotated in the frontal plane about an axis 350 extending parallel to thelength of the metatarsal 210. Rotation of distal portion 322 about axis350 can cause the proximal end of the distal portion to rotate into thesecond saddle or concavity 332 (illustrated on FIG. 8B) formed by makingthe second crescentic-shaped cut 328. In some examples, the distalportion 322 is rotated relative to the proximal portion 320 until thesagittal plane 340 bisects the crista prominence 346 on the plantar sideof the foot, as illustrated in FIG. 7. Additionally or alternatively,the distal portion 322 can be pivoted in the transverse plane (e.g.,such that the distal end of the distal portion is translated from themedial to lateral direction) to close the IMA. Further additionally oralternatively, the distal portion 322 may be pivoted in the sagittalplane (e.g., such that the distal end of the distal portion istranslated plantarly or dorsally) to correct a sagittal planemisalignment.

In some applications, the distal portion 322 is moved in multiple planes(2 or 3 planes) relative to the proximal portion 320 to move the distalportion from an anatomically misaligned position to an anatomicallyaligned position. With respect to the frontal plane, a normal firstmetatarsal will be positioned such that its crista prominence 346 (FIG.7) is generally perpendicular to the ground (e.g., bisected by thesagittal plane) and/or its sesamoid bones are generally parallel to theground and positioned under the metatarsal. This position can be definedas a metatarsal rotation of 0 degrees. In a misaligned first metatarsal,the metatarsal may be axially rotated between about 4 degrees to about30 degrees or more. Accordingly, in some applications, the distalportion 322 is moved relative to the proximal portion 320 toanatomically align the distal portion by reducing the metatarsalrotation in the frontal plane from about 4 degrees or more to less than4 degrees (e.g., to about 0 to 2 degrees) by rotating the distal portion322 with respect to the proximal portion 320.

In an anatomically misaligned metatarsal, the hallux sesamoid bones inthe foot of the patient may be rotated relative to their normal,anatomically-aligned position. The hallux sesamoids are two ovoid-shapedossicles within the flexor hallucis brevis muscles where the musclespass over the metatarsophalangeal joint (joint 232 in FIG. 2A) betweenthe first metatarsal 210 and proximal phalanx 220. There is a tibialhallux sesamoid and a fibular hallux sesamoid. FIG. 9C is a frontalplane view of first metatarsal 210 showing an example frontal planerotational misalignment of the two sesamoid bones 352. In some examples,the distal portion 322 is rotated in the frontal plane until thesesamoids 352 are generally parallel to the ground and positioned underthe metatarsal, e.g., bisected by the sagittal plane. Repositioning ofthe sesamoids after an example rotational realignment in the frontalplane is illustrated in FIG. 9D. Additional details on rotationcorrection techniques for bone portions that can be used in accordancewith the disclosure are described in U.S. patent application Ser. No.14/981,335, entitled “BONE POSITIONING AND PREPARING GUIDE SYSTEMS ANDMETHODS” and filed on Dec. 28, 2015, the entire contents of which areincorporated herein by reference.

In some examples, a clinician performing an anatomical realignmentaccording to the disclosure (for example, using one or more of thecutting techniques described with respect to FIGS. 4A-4D), may useimaging equipment within the operating suit to help visualize and guidethe realignment process. For example, the clinician may use fluoroscopyto visualize the positioning of bones during one or more portions of therealignment technique, such as during cutting and/or while realigning adistal bone portion relative to a proximal bone portion. To aidvisualization and/or movement of one bone portion relative to anotherbone portion, the clinician may insert one or more pins (e.g., metalrods) into the bone before or after making a transecting cut.

In some examples, the clinician inserts a pin into the distal portion ofthe bone before making a transecting cut (e.g., using a planar,crescentic, spherical, or other shaped cutting instrument). Additionallyor alternatively, the clinician may insert a pin into the proximalportion of the bone before making the transecting cut. As alternatives,one or both pins may be inserted after making the transecting cut,although it may be procedurally simpler to insert the pin(s) beforemaking the cut. The clinician may insert the pin in the distal portionso the tip of the pin is inserted at an angle in the lateral-plantardirection into the bone. This may result in the head of the pinprojecting out of the bone in the medial-dorsal quadrant. Otherinsertion directions can be used.

After making the transecting cut, the clinician may use the pin as aguiding instrument to facilitate movement of the distal bone portionrelative to the proximal bone portion. For example, the clinician mayapply a translating force and/or a rotary force to the pin, optionallywhile observing the amount of movement under fluoroscopic imaging, toguide the distal bone portion to a suitably realigned position. Theclinician may use the anatomical standards and/or landmarks describedabove to determine when the distal bone portion has been suitablyrealigned. In some examples, the distal bone portion is rotated untilthe sesamoid bones on the distal portion are centered plantarly. Exampleanatomical landmarks are described below with respect to FIGS. 18A and18B.

After suitably moving the distal and proximal bone portions 322, 320relative to each other, the bone portions may be fixated to provide astable orientation during healing. In some examples, the distal andproximal bone portions 322, 320 are provisionally fixated relative toeach other before permanently fixating the bone portions relative toeach other. Provisional fixation can temporarily hold the proximal boneportion 320 and distal bone portion 322 in fixed alignment relative toeach other while one or more permanent fixation devices are applied tothe bones and across the joint formed therebetween. To provisionallyfixate the bone portions relative to each other, a fixation wire may bedriven in the proximal bone portion 320 and distal bone portion 322.Additionally, or alternatively, a compression pin, such as a threadedolive pin, may be inserted through the proximal portion 320 and into thedistal portion 322, or vice versa, to provide compression andprovisional fixation between the two bone portions.

Independent of whether the proximal bone portion 320 and distal boneportion 322 are provisionally fixated together, the clinician may applya permanent fixation device to the bone portions and across the jointbetween the bone portions. The permanent fixation device can hold thebone portions in fixed alignment relative to each other, e.g., topromote healing between the bone portions in their aligned positions. Indifferent examples, one or more bone plates, pins, screws, staples, orother fixation mechanisms can be used to fixate the bones relative toeach other. FIG. 10 illustrates an example configuration of a bone plate400 that may be used to bridge the joint formed between the proximalportion and the distal portion of the first metatarsal. When using abone plate, a variety of different shaped bone plates can be used,including helical-shaped bone plates, T-shaped bone plates, and L-shapedbone plates.

Additionally, while different cutting hardware can be used to execute anosteotomy technique according to the disclosure, FIG. 10 illustrates oneexample cutting guide 410 that may be useful to perform the technique.As shown, cutting guide 410 includes a seeker portion 420 projectingplantarly from a main body 430. The seeker portion may be configured(e.g., sized and/or shaped) to be inserted in a TMT joint between firstmetatarsal 210 and medial cuneiform 222, thereby providing acomparatively stable and fixed platform from which to guide cutting. Themain body 430 of cutting guide 410 extends distally along firstmetatarsal 210 and may define a guide surface along with a cuttinginstrument can be translated to perform one or more cuts as describedherein.

As yet another example, an osteotomy correction technique may beperformed using a combination of a crescentic-shaped cut and a planar(e.g., non-curved) cut. FIGS. 11A-11C show example procedural steps thatcan be performed to correct an anatomical misalignment of a bone using acombination of crescentic-shaped and planar cuts. As shown in FIG. 11A,the first metatarsal 210 can be transected by making a crescentic-shapedcut 318 to form a proximal bone portion 320 and a distal bone portion322, as discussed above with respect to FIGS. 5A-5D. In differentexamples, the crescentic-shaped cut 318 can be made using a cuttinginstrument that makes a planar cut (e.g., planar blade, rotary cutter)that is translated through a curved arc or a curved-shaped cutting bladethat is translated linearly to form the generally crescent-shaped cut.In some examples, the crescentic-shaped cut 318 is made so the end face324 of proximal portion 320 has a concave shape while the end face 326of distal portion 322 has a corresponding convex shape.

With reference to FIG. 11B, a planar cut 470 can be made across thedistal portion 322 to form an intermediate bone portion 472. The planarcut 470 can be made prior to making the crescentic-shaped cut 318 orafter making the crescentic-shaped cut. In either case, the planar cut470 can form a new planar end face 474 on the proximal end of the distalportion 322. This can cause the crescentic-shaped end face 324previously defined by the distal portion 322 to become the proximal endface of the newly formed intermediate portion 472. The distal end face476 of the intermediate portion 472 may be planar, corresponding to theplanar end face 474 on the distal portion 322.

The planar cut 470 can be made by translating a cutting instrumentthrough the distal portion 322. The planar cut 470 may be offset fromthe crescentic-shaped end face 324 formed by making thecrescentic-shaped cut 318 (or that will be formed upon subsequentlymaking the crescentic-shaped cut in instances where the planar cut ismade first). In some examples, the planar cut 470 is offset from theterminal edge 478 of the crescentic-shaped end face 324 a distance 480ranging from 2 to 30 millimeters, such as from 7 to 25 millimeters.

In the illustrated example, the planar cut 470 is made parallel to thefrontal plane, e.g., perpendicular to the transverse plane. However, theplanar cut can be angled in the sagittal plane (either in theproximal-to-distal direction or distal-to-proximal direction), such asan angle ranging from 2 degrees to 15 degrees relative to the frontalplane 344, such as from 5 degrees to 10 degrees relative to the frontalplane.

To adjust the anatomical alignment of the distal portion 322 relative tothe proximal portion 320 and/or intermediate portion 472, the distalportion can be moved. In some examples as illustrated in FIG. 11C, thedistal portion 322 and intermediate portion 472 are translated in thetransverse plane. The distal portion 322 and intermediate portion 472can be pivoted in the transverse plane (e.g., such that the distal endof the distal portion is translated from the medial to lateraldirection) to close the IMA. As the distal portion 322 and intermediateportion 472 are pivoted, the crescentic-shaped end face 324 of theintermediate portion can translate along the arc of the correspondingcrescentic-shaped end face 326 of the proximal portion. The planar endfaces 474 and 476 of the intermediate and distal portions may not moverelative to each other during this pivoting movement.

Additionally or alternatively, the distal portion 322 can be rotated inthe frontal plane about an axis 350 extending parallel to the length ofthe metatarsal 210. Rotation of distal portion 322 about axis 350 cancause the planar end face 474 on the proximal end of the distal portion322 to rotate relative to the planar end face 476 on the intermediateportion, which may remain rotationally stationary during movement. Insome examples, the distal portion 322 is rotated relative to theintermediate portion 472 and proximal portion 320 until the sagittalplane 340 bisects the crista prominence 346 on the plantar side of thefoot, as illustrated in FIG. 7. Further additionally or alternatively,the distal portion 322 may be pivoted in the sagittal plane (e.g., suchthat the distal end of the distal portion is translated plantarly ordorsally) to correct a sagittal plane misalignment. The distal portion322 can be moved relative to the intermediate bone portion 472 and/orproximal bone portion 320 to achieve any of the anatomical alignmentpositions described herein.

After suitably moving the distal bone portion 322, proximal bone portion320, and intermediate bone portion 472 relative to each other, the boneportions may be fixated to provide a stable orientation during healing.In some examples, the distal, intermediate, and proximal bone portions322, 472, 320 are provisionally fixated relative to each other beforepermanently fixating the bone portions relative to each other. In eithercase, a clinician may apply a permanent fixation device to the threebone portions and across the two joints between the three bone portions.In different examples, one or more bone plates, pins, screws, staples,or other fixation mechanisms can be used to fixate the bones relative toeach other.

FIG. 12 illustrates an example fixation arrangement that includes afirst bone plate 490 and a second bone plate 492. The bone plates bridgethe joint formed between the distal portion and the intermediate portionas well as the joint formed between the intermediate portion and theproximal portion. In some examples, a bone plate is secured on thedorsal-medial side of the distal, intermediate, and proximal boneportions across the joints formed by transecting the first metatarsal210 into the three bone portions. Additionally or alternatively, a boneplate may be secured on a different portion of the bones.

While the foregoing discussion has generally described osteotomytechniques involving multiple crescentic-shaped cuts, it should beappreciated that the techniques may be performed without making multiplecrescentic-shaped cuts in other applications. For example, in instanceswhere a generally spherical-shaped cutting instrument is used, a singlecut may be made to transect the first metatarsal 210 and define the endsof the respective bone portions.

FIG. 13 is an illustration of an example generally spherical-shapedcutting blade 500 that can be used to transect a metatarsal during abone realignment procedure. In use, the generally spherical-shapedcutting blade 500 may be translated through an arc tracing the surfaceof an imaginary sphere to form the generally spherical-shaped cut. Thecutting blade can form one metatarsal portion having a generallyspherical-shaped projection and an opposed metatarsal portion having agenerally spherical-shaped recess. When used, the generallyspherical-shaped cutting blade 500 can have a diameter ranging from 6millimeters to 30 millimeters, although cutting blades of otherdimensions can also be used.

FIGS. 14A and 14B are illustrations of example end faces formed bytransecting a first metatarsal with generally spherical-shaped cuttingblade 500. FIG. 14A illustrates an example proximal portion 320 having aconcave or socket end face 502. FIG. 14B illustrates an example distalportion 322 having a convex or ball end face 504. The end facesillustrated in FIGS. 14A and 14B can be created be positioning the CORAof the generally spherical-shaped cutting blade 500 over the firstmetatarsal and thereafter translating the blade through the bone, e.g.,from a medial to lateral direction or vice versa. In other applications,the generally spherical-shaped cutting blade 500 may be positioned suchthat the proximal portion 320 resulting after the cut has the convex orball end face while the distal portion 322 has the concave or socket endface. This reverse orientation can be achieved by positioning the CORAof the generally spherical-shaped cutting blade 500 over the medialcuneiform and thereafter translating the blade through the firstmetatarsal, e.g., from a medial to lateral direction or vice versa. Inyet other applications, the CORA of the generally spherical-shapedcutting blade 500 can be positioned over either the first metatarsal orthe medial cuneiform and the blade translated through the firstmetatarsal from a dorsal to a plantar direction.

FIGS. 15A-15D illustrate example osteotomy procedure steps that may beperformed to realign a bone or bone portion using a planar cuttinginstrument according to the technique of FIG. 4D. FIG. 15A is a dorsalto plantar view of a first metatarsal 210 with an example frontal-planerotation and transverse-plane medial deviation, resulting in anincreased IM angle. A guide pin 650 has been inserted in the distal headof the metatarsal in preparation for further surgical procedure steps.FIG. 15B illustrates an example planar osteotomy cut line 652 thoughwhich a planar cutting instrument is passed to transect the metatarsal210 into a distal portion and a proximal portion. FIG. 15C illustratesan example frontal-plane rotational correction that can be applied tothe distal bone portion. The clinician may grasp the guide pin 650 anduse the guide pin to correct the rotation of the distal metatarsalsegment in the frontal-plane. In some examples, the clinician visualizesthe rotational realignment and use the rotational position of guide pin650 to visually guide the degree of rotational correction applied to thedistal metatarsal portion. In addition, FIG. 15D illustrates an examplelateral translation that can be applied to the distal bone portion,either before, after, or concurrent with rotating the distal boneportion in the frontal plane (FIG. 15C). The distal bone portion can betranslated laterally in the transverse plane to address thetransverse-plane medial deviation of the metatarsal, helping to reduceor eliminate the bunion “bump”. Although not illustrated, the distalbone portion can be translated in the sagittal plane in addition to orin lieu of translating the bone portion in the transverse plane.

The clinician may visually monitor the position of guide pin 650 and usethe position of the pin (e.g., the angle of rotation of the pin) todetermine when the distal bone portion is adequately realigned.Additionally, or alternatively, the clinician may view the position ofguide pin 650 and/or the position of one or more anatomical landmarks onthe distal bone portion under fluoroscopy to determine when the distalbone portion is adequately realigned. Once suitably realigned, theclinician may provisionally and/or permanently fixate the realigneddistal bone portion to the proximal bone portion, as discussed above.

FIGS. 16A and 16B are example images showing how a guide pin can be usedto help facilitate realignment of one bone portion relative to anotherbone portion. FIG. 16A illustrates a first metatarsal 210 havingfrontal-plane rotation deviation. A guide pin 650 is inserted into themetatarsal. The rotational position of guide pin 650 can be used by theclinician to help visually determine (e.g., with the unaided eye orunder fluoroscopic imaging) when the portion of the first metatarsalbeing rotationally realigned has been suitably rotated in the frontalplane. In some examples, the clinician also uses guide pin 650 as agrasping instrument to manually grasp the pin and rotate the boneportion being realigned. FIG. 16B illustrates how the portion of firstmetatarsal 210 containing guide pin 650 has been rotationally realignedin the frontal plane. The angle of the guide pin 650 has rotateddorsally with rotation of the first metatarsal 210 and the sesamoidbones of have been centered plantarly under the metatarsal. In someexamples, the first metatarsal 210 may translated in the transverseand/or sagittal plane in addition to being rotated in the frontal plane.

FIGS. 17A and 17B are additional example images showing how guide pinscan be used to help facilitate realignment of one bone portion relativeto another bone portion. FIG. 17A illustrates a first metatarsal 210having frontal-plane rotation deviation. A first guide pin 650A isinserted into the metatarsal (e.g., in a distal portion of themetatarsal) while a second guide pin 650B is inserted proximally of thefirst guide pin (e.g., in a proximal portion of the metatarsal and/ormedial cuneiform). The clinician can use the relative rotationalpositions of first and second guide pins 650A and 650B to help visuallyguide realignment of the distal portion of the first metatarsal (e.g.,with the unaided eye and/or under fluoroscopic imaging). FIG. 17Billustrates how the portion of first metatarsal 210 containing firstguide pin 650A has been rotationally realigned in the frontal planerelative to the second guide pin 650B. The angle of the first guide pin650A has rotated dorsally into alignment with the second guide pin 650B.In some examples, the first metatarsal 210 may translated in thetransverse and/or sagittal plane in addition to being rotated in thefrontal plane.

FIGS. 18A and 18B are fluoroscopic images showing example anatomicallandmarks on a distal portion of a first metatarsal that a clinician maymonitor (e.g., with the aid of fluoroscopy) to determine when the distalportion is suitably realigned relative to the proximal portion of themetatarsal. FIG. 18A is a fluoroscopic image taken from thedorsal-to-plantar direction showing a first metatarsal 210 that ismisaligned in at least the frontal plane. In this example, the distalmetatarsal head is characterized by a lateral rounding 670 in thetransverse plane (the plane in the plane of the image), which isattributable to the frontal plane misalignment. As illustrated, thelateral rounding is the profile of the plantar condyles that come intoview in the anterior-posterior projection with metatarsal frontal-planerotation. Further, FIG. 18A illustrates that the sesamoid bones 672 arerotated laterally, also attributable to the frontal plane misalignment.

FIG. 18B is a fluoroscopic image taken from the dorsal-to-plantardirection showing the first metatarsal 210 from FIG. 18A that has beenrealigned in multiple planes. As shown, the lateral side 670 of thedistal metatarsal head is substantially planar in the sagittal plane. Inaddition, the sesamoid bones 672 have rotated medially and arepositioned substantially centered plantarly under the distal portion ofthe first metatarsal. Accordingly, FIGS. 18A and 18B illustrate that theprofile of the metatarsal head and/or the position of the sesamoid bonesare anatomical landmarks visible using fluoroscopy that a clinician canuse to control realignment and determine when a distal bone portion isadequately realigned.

Various examples have been described. These and other examples arewithin the scope of the following claims.

1. A method comprising: using a guide surface of a cutting guide toguide a cutting instrument to cut a first metatarsal, the cuttinginstrument cutting the first metatarsal into a proximal metatarsalportion and a distal metatarsal portion; moving the distal metatarsalportion in at least a frontal plane and a transverse plane relative tothe proximal metatarsal portion, thereby adjusting an alignment of thedistal metatarsal portion relative to the proximal metatarsal portion;and fixating an adjusted position of the distal metatarsal portionrelative to the proximal metatarsal portion by applying at least onefixation device.
 2. The method of claim 1, wherein moving the distalmetatarsal portion in the frontal plane comprises rotating the distalmetatarsal portion until a tibial sesamoid bone and a fibular sesamoidbone are on opposite sides of a sagittal plane when viewed from thefrontal plane.
 3. The method of claim 1, wherein moving the distalmetatarsal portion in the transverse plane comprises shifting the distalmetatarsal portion laterally in the transverse plane.
 4. The method ofclaim 1, wherein moving the distal metatarsal portion in the transverseplane comprises pivoting the distal metatarsal portion laterally in thetransverse plane.
 5. The method of claim 1, wherein moving the distalmetatarsal portion in at least the frontal plane and the transverseplane further comprises moving the distal metatarsal portion in asagittal plane.
 6. The method of claim 1, wherein fixating the adjustedposition of the distal metatarsal portion relative to the proximalmetatarsal portion by applying at least one fixation device comprisesapplying at least one of a bone plate, a pin, a screw, and a stapleacross a joint separating the distal metatarsal portion from theproximal metatarsal portion.
 7. The method of claim 1, wherein fixatingthe adjusted position of the distal metatarsal portion relative to theproximal metatarsal portion by applying at least one fixation devicecomprises applying at least one bone plate across a joint separating thedistal metatarsal portion from the proximal metatarsal portion.
 8. Themethod of claim 7, wherein the at least one bone plate comprises a boneplate selected from the group consisting of a helical-shaped bone plate,a T-shaped bone plate, and an L-shaped bone plate.
 9. The method ofclaim 1, wherein cutting the first metatarsal into the proximalmetatarsal portion and the distal metatarsal portion comprises making atleast one of a planar cut, a generally spherical-shaped cut, and acrescentic-shaped cut transecting the first metatarsal.
 10. The methodof claim 1, wherein cutting the first metatarsal into a proximalmetatarsal portion and a distal metatarsal portion comprises making aplanar cut transecting the first metatarsal.
 11. The method of claim 1,further comprising, prior to using the guide surface of the cuttingguide, aligning the cutting guide relative to the first metatarsal. 12.The method of claim 1, wherein the cutting guide comprises a seeker, andaligning the cutting guide comprising inserting the seeker into atarsometatarsal joint between the first metatarsal and a medialcuneiform.
 13. The method of claim 1, further comprising inserting aguide pin into at least the distal metatarsal portion, wherein movingthe distal metatarsal portion comprises moving the distal metatarsalportion in at least the frontal plane via the guide pin.
 14. The methodof claim 13, wherein inserting the guide pin comprises inserting adistal guide pin into the distal metatarsal portion and inserting aproximal guide pin into the proximal metatarsal portion.
 15. The methodof claim 14, wherein moving the distal metatarsal portion comprisesvisualizing the distal metatarsal portion and the proximal metatarsalportion under fluoroscopy and monitoring a position of one or moreanatomical landmarks visible under fluoroscopy to control adjustment ofthe anatomical alignment.
 16. A method comprising: positioning a guidesurface of a cutting guide over a portion of a first metatarsal to becut, the cutting guide comprising a seeker offset a distance from theguide surface, wherein positioning the guide surface of the cuttingguide over the portion of the first metatarsal to be cut comprisesinserting the seeker into a joint defined by an end of the firstmetatarsal; guiding a cutting instrument along the guide surface to cutthe first metatarsal into a proximal metatarsal portion and a distalmetatarsal portion; moving the distal metatarsal bone portion in atleast a frontal plane and a transverse plane relative to the proximalmetatarsal bone portion, thereby adjusting an alignment of the distalmetatarsal portion relative to the proximal metatarsal portion; andfixating an adjusted position of the distal metatarsal portion relativeto the proximal metatarsal portion by applying at least one fixationdevice.
 17. The method of claim 16, further comprising inserting a guidepin into at least the distal metatarsal portion, wherein moving thedistal metatarsal portion comprises moving the distal metatarsal portionin at least the frontal plane via the guide pin.
 18. The method of claim16, wherein moving the distal metatarsal portion in the transverse planecomprises shifting the distal metatarsal portion laterally in thetransverse plane.
 19. The method of claim 16, wherein moving the distalmetatarsal portion in the transverse plane comprises pivoting the distalmetatarsal portion laterally in the transverse plane.
 20. The method ofclaim 16, wherein cutting the first metatarsal into the proximalmetatarsal portion and the distal metatarsal portion comprises making atleast one of a planar cut, a generally spherical-shaped cut, and acrescentic-shaped cut transecting the first metatarsal.